CN112513930A

CN112513930A - Stent expansion displays, systems and methods

Info

Publication number: CN112513930A
Application number: CN201980048432.0A
Authority: CN
Inventors: A·戈皮纳特; K·萨维吉; R·斯泰因布雷彻
Original assignee: Optical Experimental Imaging Co
Current assignee: Optical Experimental Imaging Co; LightLab Imaging Inc
Priority date: 2018-05-29
Filing date: 2019-05-29
Publication date: 2021-03-16
Also published as: JP7304367B2; JP2021525587A; US20190365480A1; EP3811333A1; JP2023123686A; WO2019232078A1; US11344373B2; JP7566084B2

Abstract

The present disclosure is directed, in part, to systems and methods for assessing stent/scaffold expansion in a blood vessel on an accelerated time scale after stent/scaffold placement and expansion. In one embodiment, the method generates a first representation of a stented segment of the vessel indicative of a level of stent expansion; determining a first end of the stent and a second end of the stent using the detected stent struts; and generating a second representation of the segment of the blood vessel by interpolating the lumen contour using the offset distances from the first end and from the second end.

Description

Stent expansion displays, systems and methods

RELATED APPLICATIONS

Priority of U.S. provisional application No. 62/677,623, filed on 29/5/2018, this application is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to the field of systems and methods for imaging a vascular system and data collection. In particular, the present disclosure relates to methods of assessing stent expansion levels and presenting relevant diagnostic information.

Background

Coronary artery disease is one of the leading causes of death worldwide. The ability to better diagnose, monitor and treat coronary artery disease can be of life saving importance. Intravascular Optical Coherence Tomography (OCT) is a catheter-based imaging modality that uses light to interrogate the coronary artery walls and generate images of the coronary artery walls for study. With coherent light, interferometry, and micro-optics, OCT can provide video-rate in vivo tomography with micron-scale resolution in diseased vessels. The use of fiber optic probes to view subsurface structures with high resolution makes OCT particularly useful for minimally invasive imaging of internal tissues and organs. This level of detail made possible with OCT allows the user to diagnose and monitor the progression of coronary artery disease.

OCT imaging of portions of a patient's body provides a useful diagnostic tool for physicians and others. For example, imaging a coronary artery by intravascular OCT can reveal the location of a narrowing or stenosis. This information helps cardiologists choose between invasive coronary artery bypass surgery and less invasive catheter-based procedures (e.g., angioplasty or stent delivery). Although stent delivery is a popular choice, it has its own associated risks.

Stents are tubular structures typically formed from mesh. It can be inserted into a blood vessel and expanded to counteract the stenotic condition that constricts blood flow. Stents are typically made of metal or polymer scaffolds. They can be placed via a catheter to the site of the stenosis. During cardiovascular surgery, a stent may be delivered to a stenosis site through a catheter via a guide wire and expanded using a balloon. Generally, stents are expanded using a preset pressure to enlarge the lumen of a stenosed vessel.

When positioning the stent, there are several factors that affect the patient's outcome. In some procedures, the stent should be expanded to a diameter corresponding to the diameter of the adjacent healthy vessel segment. Stent over-expansion can result in extensive damage to the vessel, tending it to separate, articulate, and bleed within the wall. Under-expansion of the stent may cause insufficient vessel expansion. If portions of the stent fail to contact the vessel wall, the risk of thrombosis may increase. Under-expanded stents may not restore normal flow. Proper stent expansion is a difficult problem to solve.

There are other challenges associated with stent placement and related procedures. It has been verified that visualizing stent placement relative to the wall of a vessel using an angiographic system is challenging. Manual review of the images to determine stent position on a per image basis is also prone to error.

Accordingly, there is a need for systems, methods, and devices that provide useful diagnostic information related to stent expansion.

The present disclosure addresses these challenges as well as others.

Disclosure of Invention

The present disclosure is directed, in part, to a method of evaluating stent/scaffold expansion in a vessel defining a lumen. In various embodiments, the blood vessel is an artery. The method may comprise one or more of: scanning the stented vessel using a first imaging system to obtain a first set of vessel image data; storing the first set of blood vessel image data in an electronic memory device in electronic communication with the first imaging system; detecting stent struts along a length of the stented vessel using one or more software modules; generating a first representation of a segment of a vessel indicative of a level of stent expansion; determining a first end of the stent and a second end of the stent using the detected stent struts; defining a first offset distance (D1) from the first end of the stent and a second offset distance (D2) from the second end of the stent; generating a second representation of the segment of the blood vessel using D1 and D2 in combination with the tapered profile of the segment; and assessing a level of target stent expansion along the vessel segment by comparing the first value associated with the first representation and the second value associated with the second representation at different locations along the length of the segment.

In one embodiment, scanning the blood vessel is performed using optical coherence tomography, ultrasound, x-ray based imaging, interferometric imaging, 2D imaging, MRI, 3D imaging, magnetic imaging, or optical imaging. In one embodiment, the vessel receives one or more stents during a first procedure, wherein the scanning of the stented vessel is performed as an extension of the first procedure as a diagnostic analysis.

In one embodiment, the first representation is a first lumen profile of the stented vessel, wherein the lumen profile is generated based on an actual level of expansion of the stent along the length of the segment. In one embodiment, the second representation is a second lumen profile generated based on geometric values of the blood vessel for each of D1 and D2, wherein the second lumen profile is interpolated based on such geometric values and the tapered profile of the blood vessel.

In one embodiment, the method further comprises detecting one or more side branches along the segment, wherein the interpolation of the second lumen contour is generated using the one or more detected side branches. In one embodiment, the geometric value of the blood vessel is selected from the group consisting of area, diameter, chord, euclidean distance metric and volume.

In one embodiment, wherein assessing the level of target stent expansion further comprises determining the degree of stent expansion using a ratio of a first value of the first lumen profile to a second value of the second lumen profile at a plurality of locations along the segment relative to a stent expansion threshold.

In one embodiment, the first representation includes one or more views of the blood vessel, wherein the one or more views of the blood vessel display representations of the detected stent struts and a lumen of the blood vessel. In one embodiment, scanning of the stented vessel is performed using optical coherence tomography, angiography, ultrasound, x-ray, optical imaging, pressure sensing, flow sensing, and tomographic imaging. In one embodiment, scanning of the stented vessel is performed using an intravascular data collection probe that is pulled back through the vessel. In one embodiment, the scanning of the stented vessel is performed using one or more shadows or reflections from the first set of vessel image data.

In one embodiment, when the stent is placed, D1 and D2 are selected based on proximity to a user selected target landing zone. In one embodiment, the method further comprises generating, using the one or more computing devices, a vessel lumen profile after deploying the stent in the vessel. In one embodiment, the method further comprises displaying one or more views of the vessel and/or the first vessel representation, and displaying one or more visual cues indicative of the area of the under-expanded stent along the length of the vessel segment.

In one embodiment, the method further comprises detecting a side branch along a length of the section of the blood vessel and displaying the side branch relative to the lumen. In one embodiment, the side branches are displayed as dots, ellipses, circles, or other shapes relative to the first representation. In one embodiment, the first representation is displayed using a user interface of the imaging system. In one embodiment, the method further includes scanning the vessel with an angiography system and co-registering the angiography data with the detected stent struts and the first visual cue indicating stent expansion above a stent expansion threshold and the second visual cue indicating stent expansion below the stent expansion threshold. In one embodiment, the method further comprises visually emphasizing an area comprising the first representation of the stent. In one embodiment, the user interface emphasizes the region by changing the contrast, intensity, color of another visual element relative to the region. In one embodiment, D1 and D2 are selected from distances in the range of about 0.1mm to about 1.0 mm. In one embodiment, D1 and D2 are about 0.4 mm.

The present disclosure is directed, in part, to a processor-based system for assessing stent expansion in a stented vessel. The system includes one or more memory devices; and a computing device in communication with the memory device, wherein the memory device includes instructions executable by the computing device to cause the computing device to: storing the first set of blood vessel image data in an electronic memory device in electronic communication with a first imaging system, the first set of blood vessel image data generated by scanning blood vessels using the first imaging system; detecting stent struts along a section of a stented vessel using one or more software modules; generating a first representation of a segment of a vessel indicative of a level of stent expansion; determining a first end of the stent and a second end of the stent using the detected stent struts; defining a first offset distance (D1) from the first end of the stent and a second offset distance (D2) from the second end of the stent; generating a second representation of the segment of the blood vessel using D1 and D2 in combination with the tapered profile of the segment; and assessing a level of target stent expansion along the vessel segment by comparing the first value associated with the first representation and the second value associated with the second representation at different locations along the segment.

In one embodiment, the first value is a first area or a first diameter, wherein the second value is a second area or a second diameter. In one embodiment, the system is one or a combination of an optical coherence tomography system, an angiographic system, an ultrasound system, an x-ray system, a CT scanning system, an optical imaging system, a pressure sensing system, a flow sensing system, and a tomographic imaging system.

OCT data can be used to generate 2-D views (e.g., cross-sectional and longitudinal views of a vessel) before or after a procedure related to initial stent placement or correction of a stent. OCT data obtained using the data collection probe and various data processing software modules can be used to identify, characterize, and visualize the stent and/or one or more characteristics associated with the stent and/or the lumen in which the stent is disposed.

In one embodiment, the one or more outputs are a visual depiction of the target stent contour overlapping one or more regions of the vessel lumen contour. In one embodiment, the one or more outputs are a comparative measure of the change in the measured parameter or the calculated parameter relative to a segment of the blood vessel. In one embodiment, the parameter is selected from the group consisting of fractional flow reserve, flow rate, vascular impedance ratio, virtual fractional flow reserve, simulated fractional flow reserve, measured fractional flow reserve, and pressure measurement.

In one embodiment, the method includes generating, using the one or more computing devices, a vessel lumen contour after placing the stent in the vessel, including generating a representation of a segment of the vessel using a second set of intravascular data obtained with respect to the vessel. In one embodiment, a first set of intravascular data is obtained during a first optical coherence tomography session. In one embodiment, a second set of intravascular data is obtained during a second optical coherence tomography session.

One or more devices may display one or more user interfaces as well as intravascular data or other information derived from such data. Intravascular data can be obtained using IVUS or OCT based data collection systems and probes or other imaging modalities. The method may be implemented using one or more computing devices and memory storage as follows: these computing devices and memory stores receive intravascular data and user input via a Graphical User Interface (GUI) and include one or more image processing and frame selection software components. The computing device may be a microprocessor, ASIC, or other processor suitable for use with an intravascular imaging system.

While the present invention is directed to various aspects and embodiments, it should be understood that the various aspects and embodiments disclosed herein may be suitably integrated together, in whole or in part. Thus, each of the embodiments disclosed herein may be incorporated into a given implementation to varying degrees as appropriate in each aspect. Furthermore, the various software-based tools for addressing medical imaging issues and other related challenges and problems and portions of the foregoing may be used in medical applications and other applications for displaying information related to stents, vessels, and their two-dimensional and three-dimensional views, without limitation. Other features and advantages of the disclosed embodiments will become apparent from the following description and the accompanying drawings.

While the present disclosure is directed to various aspects and embodiments, as well as other features, as described and depicted herein, it should be understood that each of the foregoing disclosed herein may be suitably integrated together, in whole or in part. Thus, each of the embodiments disclosed herein may be incorporated into a given implementation to varying degrees as appropriate in each aspect. In addition, the various stent expansion diagnostic tools described herein may be used with various imaging modalities.

Other features and advantages of the disclosed embodiments will be apparent from the following description and the accompanying drawings.

Drawings

The present application contains at least one figure executed in color. Copies of this patent application publication with color drawing(s) will be provided by the office upon request and payment of the necessary fee.

The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating principles. The drawings are to be regarded as illustrative in all respects and not intended to limit the disclosure, the scope of which is defined solely by the claims.

Fig. 1A shows a schematic view of an imaging and data collection system suitable for imaging arteries, stents, and other cardiovascular system components, according to an illustrative embodiment of the present disclosure.

Fig. 1B shows a schematic view of an imaging and data collection system suitable for imaging arteries, stents, and other cardiovascular system components and including multiple displays, according to an illustrative embodiment of the present disclosure.

Fig. 2A is a graphical user interface displaying stent expansion analysis results related to co-registered angiographic data, profile views, and other intravascular imaging views, according to an illustrative embodiment of the present disclosure.

Fig. 2B is a graphical user interface displaying stent expansion analysis results in relation to a profile view according to an illustrative embodiment of the present disclosure.

Fig. 3 is a graphical user interface displaying stent expansion analysis results related to a contour view and stent struts detected in another arterial view, according to an illustrative embodiment of the present disclosure.

Fig. 4A and 4B are schematic representations of a blood vessel including one or more side branches as shown that are suitable for generating a lumen profile model suitable for analyzing stent expansion, according to an illustrative embodiment of the present disclosure.

Fig. 5A is a graphical user interface displaying stent expansion analysis results related to co-registered angiographic data, profile views, arterial measurements, and other intravascular imaging views, according to an illustrative embodiment of the present disclosure.

Fig. 5B is a graphical user interface displaying stent expansion analysis results and details related to balloon size suitable for adjusting the level of stent expansion according to an illustrative embodiment of the present disclosure.

Fig. 6A and 6B are graphical user interfaces displaying stent expansion analysis results relative to a profile view and stent struts detected in another arterial view, according to an illustrative embodiment of the present disclosure.

Fig. 7 is a graphical user interface displaying stent expansion analysis results relative to a contour view and stent struts detected in another arterial view, according to an illustrative embodiment of the present disclosure.

Fig. 8 is a schematic diagram of a software-based image processing pipeline adapted to analyze stent expansion and other artery-related parameters according to an illustrative embodiment of the present disclosure.

Detailed Description

The present disclosure is directed, in part, to systems and methods that address the following technical problems: the expanded stent is detected and diagnostic information is provided to support supplemental stent expansion and balloon selection in the context of a vessel imaging, analysis and diagnostic system. As a challenge related to stent placement and proper expansion, coordinating angiographic images with respect to one or more imaging modalities such that regions of an under-expanded stent can be easily identified on an accelerated time scale is an important technical challenge. The use of co-registration and generation of various lumen profiles may be used to address this challenge.

If the stent is under-expanded, it can lead to vessel failure one year after the initial treatment. Therefore, assessing stent expansion while the patient is in the catheter laboratory immediately after stent placement, generating a representation of the stent relative to the artery into which it is placed and a corresponding angiographic view is a solution to the problem of achieving proper stent expansion. The use of the model to generate an appropriate/full-expanded luminal model is also described to provide diagnostic guidance regarding stent expansion.

Properly expanding a stent in a vessel (e.g., a coronary artery) is a significant target result because it increases the likelihood that a constricted stenotic region of an artery will successfully expand and remain expanded based on proper balloon selection and stent placement, while using an imaging modality to notify the end user. Addressing this technical problem mitigates adverse consequences (e.g., bypassing surgical or other procedures).

FIG. 1A shows a system 5 that includes various data collection subsystems suitable for: collecting data, or detecting a characteristic of subject 4, or sensing a condition of subject 4, or otherwise diagnosing subject 4. In one embodiment, the subject is disposed on a suitable support 19 (e.g., a table, bed and chair, or other suitable support). Typically, the subject 4 is a human or another animal having a particular region of interest 25.

The data collection system 5 includes a non-invasive imaging system such as magnetic resonance, x-ray, computer-assisted tomography, or other suitable non-invasive imaging technique. As shown as a non-limiting example of such a non-invasive imaging system, an angiographic system 21 is shown, for example, suitable for generating canines. The angiography system 21 may comprise a fluoroscopy system. The angiography system 20 is configured to non-invasively image the subject 4 such that a frame of angiography data (typically in the form of a frame of image data) is generated while a pullback procedure is performed using the probe 30 such that a blood vessel in a region 25 of the subject 4 is imaged using angiography in one or more imaging techniques (e.g., OCT or IVUS).

In one embodiment, the angiography system 21 communicates with an angiography data storage and image management system 22, which angiography data storage and image management system 22 may be implemented as a workstation or server. In one embodiment, the data processing related to the collected angiographic signals is performed directly on the detectors of the angiographic system 21. Images from the system 20 are stored and managed by an angiographic data store and image manager 22. Other imaging systems disclosed herein may replace or enhance system 21.

The present disclosure relates in part to software-based methods, systems, and apparatus adapted to evaluate and delineate other vascular information or other intravascular information of interest. Various user interface views are shown in fig. 2A, 2B, 3, 5A, 5B, 6A, 6B, and 7 as follows: these user interface views show details regarding stent expansion, vessel representation, and lumen profile (partially expanded lumen and fully expanded lumen) relative location of stent endpoints in both angiograms and other imaging modalities (e.g., OCT). In particular, these systems and methods involve a technical solution to the technical problem of: stent under-expansion is generally detected and mitigated, with particular emphasis on expansion of the stent using a guided imaging/diagnostic system. Imaging data and data derived therefrom (e.g., a vessel representation) are generated and displayed as part of a user interface to provide diagnostic information quickly. These may take the form of ratios of different lumen profiles and values (e.g., area, diameter, or other geometric values) at corresponding locations along their lengths.

The system of fig. 1A includes various components for imaging one or more arteries and/or components of the cardiovascular system using one or more of CT scanning, ultrasound, IVUS, x-ray based imaging modalities, magnetic resonance imaging, optical coherence tomography, infrared, laser-based imaging, and other imaging modalities for intravascular and extravascular imaging. In one embodiment, the system server 50 or workstation 85 handles the functions of the system 22. In one embodiment, the entire system 5 generates electromagnetic radiation, such as x-rays. The system 22 also receives this radiation after it has passed through the subject 4. In turn, the data processing system 22 uses the signals from the angiography system 21 to image one or more regions of the subject 4, including the region 25.

As shown in this particular example, the region of interest 25 is a subset of a blood vessel or peripheral vasculature (e.g., a particular blood vessel). The subset can be imaged using OCT, ultrasound, or one of the other imaging modalities disclosed herein, alone or in combination. In one embodiment, the region of interest may include a stent. The stent may be imaged at different points in time (e.g., after deployment, and after supplemental stent expansion).

A catheter-based data collection probe 30 is introduced into the subject 4 and is disposed in the lumen of a particular blood vessel (e.g., such as a coronary artery). The probe or other device including a balloon may also be used to increase the level of stent expansion in response to detecting an under-expanded stent using one or more imaging modalities.

The probe 30 can be various types of data collection probes, such as, for example, an OCT probe, an FFR probe, an IVUS probe, a probe combination feature of two or more of the foregoing, and other probes suitable for imaging within a blood vessel. In one embodiment, the balloon delivery device is moved along a guide wire (for the imaging probes disclosed herein). In one embodiment, the probe 30 generally includes a probe tip, one or more radiopaque markers, an optical fiber, and a torque wire. In addition, the probe tip includes one or more data collection subsystems, such as a beam guide, an acoustic beam guide, a pressure detector sensor, other transducers or detectors, and combinations of the foregoing.

For probes that include a beam director, the optical fiber 33 is in optical communication with the probe having the beam director. The torque wire defines a bore in which the optical fiber is disposed. In fig. 1A, the optical fiber 33 is shown without a torque line around it. In addition, the probe 30 also includes a sheath, for example, a polymer sheath (not shown) that forms a portion of the catheter. An optical fiber 33, which in the context of an OCT system is part of the sample arm of the interferometer, is optically coupled to a Patient Interface Unit (PIU)35 as shown.

The patient interface unit 35 includes a probe connector adapted to receive and optically couple with an end of the probe 30. Typically, the data collection probe 30 is disposable. The PIU 35 includes appropriate fittings and elements based on the type of data collection probe used. For example, the combination of OCT and IVUS data collection probes requires OCT and IVUS PIUs. The PIU 35 also typically includes a motor adapted to pull back the torque wire, sheath, and optical fiber 33 disposed therein as part of the pulling back process. In addition to being pulled back, the probe tip is also typically rotated by the PIU 35. In this way, the blood vessel of the subject 4 may be imaged longitudinally or via a cross-section. The probe 30 may also be used to measure a particular parameter (e.g., Fractional Flow Reserve (FFR) or other pressure measurement).

In turn, the PIU 35 is connected to one or more intravascular data collection systems 42. The intravascular data collection system 42 can be an OCT system, an IVUS system, another imaging system, and combinations of the foregoing. For example, where probe 30 is an OCT probe, system 42 may include a sample arm of an interferometer, a reference arm of an interferometer, a photodiode, a control system, and a patient interface unit. Similarly, as another example, in the case of an IVUS system, the intravascular data collection system 42 may include ultrasound signal generation and processing circuitry, a noise filter, a rotatable joint, a motor, and an interface unit. In one embodiment, the data collection system 42 and the angiography system 21 have a shared clock or other timing signal configured to synchronize the angiography video frame time stamps and the OCT image frame time stamps.

Various extravascular imaging systems (e.g., angiographic systems) may image a given region of interest (e.g., a stent in various expanded states). The extravascular imaging data may be co-registered with the intravascular imaging data. Various displays, such as that shown in fig. 1B, may be used to display the output of the intravascular imaging modality and the output of the extravascular imaging modality with respect to a patient in a catheter laboratory.

In addition to the invasive and non-invasive image data collection systems and apparatus of fig. 1A, various other types of data may be collected regarding the region 25 of the subject and other parameters of interest of the subject. For example, the data collection probe 30 may include one or more pressure sensors (e.g., such as pressure lines). The pressure line can be used without adding OCT or ultrasound components. Pressure readings may be taken along a segment of a blood vessel in region 25 of subject 4.

Such readings may be relayed through a wired connection or via a wireless connection. As shown in the fractional flow reserve FFR data collection system, the wireless transceiver 48 is configured to: pressure readings are received from the probe 30 and transmitted to the system or more locations along the vessel being measured to generate FFR measurements. One or

more displays

82, 83 may also be used to display angiography frame data, OCT frames, user interfaces for OCT data and angiography data, and other controls and features of interest.

Intravascular image data (e.g., frames of intravascular data generated using the data collection probe 30) can be routed to the data collection processing system 42, with the data collection processing system 42 being coupled to the probe via the PIU 35. The non-invasive image data generated using angiography system 22 may be transmitted to, stored in, and processed by one or more servers or workstations (e.g., co-registration server 50 workstation 85). In various embodiments, a video frame grabber apparatus 55 (e.g., a computer board configured to acquire angiographic image data from the system 22) may be used.

In one embodiment, server 50 includes one or more co-registration software modules 67, and these co-registration software modules 67 are stored in memory 70 and executed by processor 80. The server 50 may include other typical components for a processor-based computing server. Alternatively, more databases (e.g., database 90) may be configured to receive the generated image data, the parameters of the subject, and other information generated by, received by, or communicated to database 90 by one or more of the system devices or components shown in fig. 1A. Although the database 90 is shown as being connected to the server 50 while being stored in the memory of the workstation 85, this is merely one exemplary configuration. For example, software modules 67 may run on a processor of workstation 85 and database 90 may be located in a memory of server 50. By way of example, an apparatus or system for running various software modules is provided. In various combinations, the hardware and software described herein may be used to obtain frames of image data, process such image data, and register such image data.

As additionally noted herein, software modules 67 may include software (e.g., preprocessing software, transformations, matrices), as well as other software-based components to: these components are used to process image data or in response to patient triggers to facilitate: the co-registration of different types of image data is performed by or otherwise performed by other software-based components 67. Modules may include lumen detection using scan line-based or image-based methods, stent detection using scan line-based or image-based methods, indicator generation, stent expansion assessment and assessment, stent landing zone detection, and indication of a deployed stent; angiographic and intravascular imaging co-registration, and other modules supported and programmed to perform the methods disclosed herein.

Database 90 may be configured to receive and store angiographic image data 92, such as image data generated by angiographic system 21 and obtained by frame grabber 55 server 50. The database 90 may be configured to receive and store OCT image data 95, e.g., image data generated by the OCT system 42 and obtained by the frame grabber 55 server 50.

Further, subject 4 may be electrically coupled to one or more monitors (e.g., such as monitor 49) via one or more electrodes. The monitor 49 may include, but is not limited to, an electrocardiogram monitor configured to: data relating to cardiac function is generated and various states of the subject are shown, such as systole and diastole. Knowing the cardiac phase can be used to assist in tracking the vessel centerline because the geometry of the heart, including the coronary arteries, is approximately the same at a particular cardiac phase, even over different cardiac cycles.

The use of arrows to illustrate directionality, or the absence of such arrows in a given figure, is not intended to limit or require the direction in which information can flow. For a given connector, e.g., the arrows and lines shown in fig. 1A as connecting elements, information may flow in one or more directions or in only one direction, as appropriate, for a given embodiment. The connection may comprise a variety of suitable data transfer connections, such as optical, electrical wire, power, wireless, or electrical connections.

One or more software modules may be used to process frames of angiographic data received from an angiographic system (e.g., system 22 shown in fig. 1A). Various software modules may be used in a given embodiment of the disclosure, which may include, but are not limited to, software, components thereof, or one or more steps of a software-based or processor-executed method.

The system of fig. 1A and 1B is adapted to display intravascular image data and extravascular image data. In particular, the system is advantageous for stent planning and assessment of stent expansion and assessment of target stent expansion. In one embodiment, the stent expansion threshold may be provided by a diagnostic system (e.g., OCT, IVUS, or other image data collection system), or such a threshold may be adjusted and set by an end user via a user interface. In one embodiment, the stent expansion threshold for identifying areas of stent under-expansion ranges from about 80% to about 90%. Thus, if a stent is expanded to a level of 48% at a first location along its length, the stent is identified or indicated with one visual cue or marker, while if in another region the stent is expanded to a level at or above a threshold, the stent is identified with another visual cue or marker.

FIG. 1B shows a catheter laboratory established by components of an imaging and data collection system (e.g., the system of FIG. 1A) for performing OCT, FFR, IVUS, angiographic, CT scan, or other types of imaging, measurement, and assessment of one or more arteries of a patient. The user may interact with the data collection system through the various displays shown, or otherwise access and display the stored image data. An exemplary user interface showing intravascular imaging data and stent expansion data co-registered with angiographic data is displayed. A support member 115 (e.g., an accessory) is laid on a table, bed or other support 120. In one embodiment, support member 115 may be part of support 120, and the controller may be directly attached to support 120.

In one embodiment, the controller may include any suitable input device and may have been used to navigate user interface screens and parameters (e.g., target stent expansion values and other stent expansion thresholds). In one embodiment, the controller includes an attachment device 60, such as a clip for mounting as shown. The controller may be used to display and navigate a graphical user interface displayed on one or more monitors or displays 123. In one embodiment, the monitor may be mounted on a ceiling suspension. The graphical user interface 127 may be displayed on a given monitor. Two exemplary graphical user interfaces 127a, 127B are shown in fig. 1B, including stent expansion and co-registered intravascular data, such as OCT data and angiography data.

In one embodiment, the controller has a feature set configured to map to commands and menus available to the user as part of the graphical user interface 127. The angiography or other imaging systems disclosed herein 125 can be positioned relative to the support 120 to obtain x-rays of the patient while another data collection procedure (e.g., an OCT procedure) is in progress. The graphical user interface 127 may display such OCT, angiographic, FFR, IVUS, and other data of interest to the user. The controller is configured to navigate through menus and image display features that control the interface 127 and present it to the user. Co-registration of angiographic data with intravascular imaging supports assessment of stent expansion levels.

In one embodiment, a healthy lumen profile is effectively simulated using a first geometry value for simulating a distal end of a healthy blood vessel and a second geometry value for a proximal end of a healthy blood vessel. In one embodiment, the geometric values are determined at positions that are offset or shifted relative to the contour of the stented vessel. These shift or offset values are shown in the various figures as D1 and D2. The geometric value may be a cross-sectional area, a diameter, a chord, a flow value, or other value suitable for interpolating a healthy lumen profile. The simulated healthy lumen profile can then be compared to the stent profile by proportionally comparing the geometric values of each respective profile.

The present disclosure describes systems and methods as follows: the system and method are used to delineate regions at stent under-expansion and at a target expansion level relative to a representation of a vessel generated using intravascular data to facilitate target balloon placement and sizing of a placed stent. Optical coherence tomography and other imaging modalities can be used to generate various vessel representations and to perform various image data processing techniques to detect and/or visually represent the lumen L, stent struts SS, side branches SB, and other components as shown and described herein.

One or more stent expansion metrics may be used. In one embodiment, the stent expansion metric may be adjusted by the end user. Thus, the physician may set the stent expansion threshold as a percentage of stent expansion, such as 90% or another percentage. Such a threshold for delineating whether the stent has expanded to this 90% level is shown in fig. 2A by legend 231, which shows an underexpanded region along the lumen contour of the stented vessel based on the threshold, a red region, also shown as region 220. In turn, the area along the length of the stent in which it has been expanded to 90% or above the threshold is shown as white, or as area 225. The Minimum Stent Area (MSA) in the vessel is also shown in the figures by cursor 227 and MSA.

If stent under-expansion has been detected in one or more regions of the vessel that are part of the user interface, a marker 220 (e.g., a red color or another visual cue) may be used to show the physician the region where the stent has expanded to a target expansion level (90% in this example), or above that expansion level: region 225. In this manner, the end user may choose to select balloons based on the appropriate diameter to achieve a target level of expansion, and can reference angiographic images and other imaging data to locate the selected balloons and increase the expansion of one or more stents in the area in which they are under-inflated.

Fig. 5B shows an updated view of a vessel representation showing white regions 225 above the N% dilation threshold, and shaded regions 220 below the N% threshold. The user interface assemblies showing balloons B1, B2, B3, and B4 having various diameters may be used to overlay them on the drawings or measurements may be performed with respect to various representations to select the appropriate balloon diameter. Balloon size is provided based on the level of stent expansion (which is required based on the target expansion threshold or target). In one embodiment, the balloon size is calculated based on the unexpanded diameter of the artery at one or more locations. In one embodiment, the balloon is a movable graphical element that may be user-selected and positioned relative to a given arterial view as described herein. Exemplary balloon B4 is shown placed in an artery at region 230 overlapping the MSA. The region is a location where expansion is warranted based on stent expansion analysis and a threshold.

Regions of the stent shown as properly expanded (e.g., at a 90% level, or above a 90% level) may retain their current level of expansion while allowing the end user to address areas of under-expansion. Selecting the appropriate balloon diameter allows the user to quickly return to the patient, locate the stent on the angiogram and in the under-expanded region, and use the lumen profile views shown herein as a guide to position the balloon in the under-expanded region or regions, and further expand the stent before ending the overall session in the catheter lab and releasing the patient. Using these various technical diagnostic tools, as well as lumen contours and expansion ratios, stent placement that may lead to the need for bypass can be corrected and the likelihood of successful patient outcomes increased.

To further address the problem of properly expanding stents, co-registration is performed between stent location and expansion level and the angiographic system. Fig. 2A illustrates an overall user interface generated using imaging data from two or more imaging modalities. Shown in the angiographic interface panel 205 are angiographic images showing the reference positions R1 and R2, which are generated after stent detection is performed on the second imaging modality (e.g., OCT, ultrasound, or otherwise). The region of the under-expanded stent 220 is shown in the angiographic view 205 and the lumen contour view 211. A cross-section of the blood vessel at the Cutting Plane (CP) is shown in the interface panel 205. The average diameter values are shown in this panel as lumen L and stent strut shading. The cutting plane is divided into two parts, labeled B and Y, which can be color coded as a blue line and a yellow line.

Fig. 2A shows an exemplary output of a diagnostic result for guiding an end user after a stent has been placed in a blood vessel. The various diagnostic results are organized in a graphical user interface 200. As shown, various panels or regions of the graphical user interface 200 are shown. These include a top left panel 205 displaying angiographic image data that is co-registered with one or more relevant images or vessel representations. In addition to the common interface display shown in fig. 2A, an auxiliary display may be used to display the angiographic diagnostic interface 205.

The longitudinal view is shown as part of the interface panel 215, which also shows the various stent struts SS in the longitudinal view of the vessel being imaged. Co-registration has been performed between the angiographic image and the lumen contour view 211. The lumen profile view includes a highlighted HL region designed to attract the attention of the user. In this portion of the outline, the cutting plane line CP or 240 corresponds to line segments B and Y, which are shown together in the other views of the intravascular image shown in

panels

209 and 215. The dark lumen L is shown in the middle of the lumen profile view. The stent is encoded with visual cues as shown in

regions

220 and 225. These correspond to legend 231, legend 231 is used to show visual cues for stent under-expansion and expansion above a target expansion threshold (shown as 90% in fig. 2A). The distal direction is to the left and the proximal direction is to the right.

The minimum bracket area MSA or 245 is shown and is also tracked using the vertical line cursor 227. MSA is the narrowest region of the scaffold. Furthermore, the region 220 clearly extends into the vessel wall representation of the constraining lumen L and is shown as narrowing relative to the vessel wall representation. In one embodiment, the MSA is identified as the region for balloon deployment to adjust stent expansion after initial deployment. These regions 220 show areas where the stent has not been properly expanded to the 90% expansion threshold. The region 225 shown on the left side of the cutting plane 240 is dilated at or above the 90% threshold. These representations allow the end user to return to the patient and place the balloon on the delivery catheter while the guide wire is still in the vessel and position the balloon using real-time angiography and referring to the view shown in fig. 2B to properly place the balloon with the correct diameter to inflate the target region 225. These various tools solve the complex technical problem of properly expanding the stent. This procedure reduces the overall time a patient spends in the catheter lab by accelerating subsequent stent expansion if the area requires its presence.

These systems, devices, and methods are implemented when a subject is evaluated using a diagnostic method (e.g., one or more cardiac imaging modalities) for the first time. These imaging modalities may include, but are not limited to OCT, IVUS, computer-assisted tomography, MRI, angiography, x-ray, pressure data-based models of cardiac and/or vascular operation and status.

The present disclosure is directed, in part, to systems, methods, and apparatus for evaluating a stent that has been placed in a vessel relative to one or more planning stages and contours obtained with respect to the vessel or stent. Intravascular data collection systems and associated probes (e.g., Optical Coherence Tomography (OCT), or intravascular ultrasound (IVUS), or other intravascular data collection modalities) can be used to obtain contours and information related to the vessel or stent. Further, the present disclosure provides an automated method for a user (e.g., a clinician or other person) to assess whether a stent placed in a vessel has expanded to an appropriate level, such as a substantially optimal level or other measure of appropriateness. In one embodiment, these metrics may be specified by a user.

The present disclosure is directed, in part, to a method of assessing stent placement in a vessel. The method includes generating, using one or more computing devices, a representation of a segment of a blood vessel using a first set of intravascular data obtained about the blood vessel in which a stent has been positioned in the blood vessel. This is shown in various lumen profile views 211, 21lb, 21lc, 211d, 211e (see fig. 2A, 2B, 5A, 5B, 6A, and 6B), where the stent is shown, and where the regions are shown properly expanded and under-expanded relative to an expansion threshold of N%. Fig. 6A and 6B show

user interfaces

320, 321, the

user interfaces

320, 321 including stent struts 325 detected in the bottom panel and lumen profile views 211d and 221e showing MSA, EXP, and an expanded region with a threshold of about 90% (see legend 231). A region 220 that would benefit from further expansion is shown in each respective lumen profile view. These maps may also be co-registered with the angiographic system.

As part of the overall system and method, various imaging processing techniques are performed using a system (e.g., the system disclosed herein, including with respect to fig. 1A, 1B, and 8). The image processing steps may include lumen boundary detection, which corresponds to the boundary between the lumen L and the vessel wall (which the vessel wall constrains), stent detection, side branch detection, and others. The lumen detection informs the stent detection as it gives which positions the stent will be present in the image relative to.

The lumen detection software may include one or more steps. For example, to perform lumen detection in one embodiment, a filter or other image processing device may be applied to the two-dimensional image to detect edges in the image that indicate lumen boundaries. In another embodiment, a scan line based approach is used. During one or more pullbacks, optical or ultrasound signals are collected as scan lines with respect to the vessel and one or more stents disposed in the lumen of the vessel. In one embodiment, lumen detection software executing a computing device generates one or more images from a set of scan lines using the computing device. Lumen detection may also be performed using other image data sets from other imaging systems.

Once the stent struts are detected, they may be displayed as shown in the various images. After stent detection, and as part of the generated lumen contour view, offset distances D1 and D2 are generated. These may be shifts in distance to the left and right (proximal and distal) or vice versa. In fig. 2A, these references are shown by lines R1 and R2.

In fig. 2B, R1 and R2 are shown in dashed lines. The end points of the stent are shown by vertical lines EP1 and EP2, which are the first end point and the second end point of the stent. These may be detected automatically once the stent has been detected by the stent detection software module. Stent endpoints are used to generate reference lines R1 and R2, reference lines R1 and R2 being automatically generated lines at a distance from the lumen. These distances are D1 and D2, as indicated by the double-headed arrows in FIG. 2B. The area of the lumen at these offset distances is also shown. More distal side offset by distance D1The product is shown as 8.5mm²And a larger proximal area of another offset distance D2 is shown as 11.23mm². The lengths of D1 and D2 are generally equal, but may vary. They are typically a relatively short distance from the stent end points and are in the range of about 0.1mm to about 1 mm. Values of about 0.4mm or about 0.5mm, for example, are desired, but other offset distances may be selected. The first reference line R1 may be a distal reference and the second reference line R2 may be a proximal reference, or vice versa.

The offset distances D1 and D2 are used for movement a distance away from the stent endpoints because the lumen area, distance, or other geometric value at these points is used to generate another lumen profile with a tapered profile 290, such as shown in 21la (see fig. 3) and 211f (see fig. 7). Stent placement may be considered a proxy for a healthy region of a blood vessel. The selection of stent endpoints may itself have various errors due to the viewing plane, the output of the stent detection software module, and reflections from stent struts at the endpoints, blooming effects, and other factors.

Thus, selecting position offsets D1 and D2 from stent endpoints allows for geometric values of the lumen profile (e.g., the area or diameter of the lumen to be selected at two points). These values may be used to interpolate the tapered profile 290, and the tapered profile 290 may be used as a fully expanded lumen profile. Thus, by interpolating such a lumen contour 290 (which corresponds to the result if no stent is needed and there is no stenosis between reference lines R1 and R2), the lumen contour may be generated using image data processing software. The lumen profile corresponding to a fully expanded lumen spanning the same area as the stent allows for the calculation of the expansion ratio at each location along the stented area.

In particular, the ratio of the cross-sectional area, or diameter, or another value from the stented lumen profile may be compared to the corresponding cross-sectional area, or diameter, or another value from the interpolated, fully expanded lumen profile to generate the stent expansion threshold N%. In fig. 7, for example, the dashed tapered profile shows what a fully dilated lumen would look like if the tissue was not stenotic. This can be compared to area or diameter values obtained from lumen contours generated after stent detection to show the amount of expansion at different points. In one embodiment, the minimum expanded frame 48% (EXP) is also automatically invoked, as shown in fig. 2B, 3, and 7. The frame indicates at least the location of the stent that is expanded. As a result, this can be used as a target for further expansion with a balloon. Co-registration with angiography may further help guide such balloon placement.

In one embodiment, the method includes generating and displaying the dilation level using an N% based dilation ratio obtained using a first representation of the vessel (based on stent dilation) and an interpolated dilated second representation (generated in the absence of a stent). Simulation of a healthy lumen profile representation facilitates generation of a metric to assess the stent expansion level and to show when the metric is met (expansion above N%) or not (expansion not enough to reach N% at position X). These representations may be obtained using intravascular data or other imaging data. The foregoing steps are performed such that the representation is co-registered with one or more angiographic images of the blood vessel. In view of this diagnostic representation of the imaging data, the user may then place the stent in the stenosis identified as the target for stent placement.

Furthermore, after one or more stents have been placed in the artery, a second imaging session is performed, for example a second intravascular pullback is performed during angiography. A second representation of the artery may be generated and the one or more stents repositioned or expanded may be assessed.

The present disclosure relates in part to a processor-based stent placement evaluator or evaluation system. The system or evaluator comprises one or more memory devices; and a computing device in communication with the memory device, wherein the memory device includes instructions executable by the computing device such that, after performing stent detection, the computing device generates one or more representations of blood vessels such that a level of stent expansion achieved relative to a threshold or other metric may be displayed by appropriate indicia or graphical user interface elements to thereby quickly present information to an end user to reduce the time spent by a subject in a catheter laboratory. The user may use the interface features (e.g., as shown in fig. 5A) to measure blood vessels and various parameters. Furthermore, once diagnostic information is available to the end user, they can select the appropriate balloon based on the desired diameter to further expand the stent and thereby increase blood flow in the stenosis and avoid subsequent procedures.

Various user interface panels are shown in FIG. 5A. Various measurements may be determined (by using various software modules and operations for the software pipeline in FIG. 8) and displayed as shown in measurement interface panel 267. For a given lumen profile, the area, average diameter, radius, minimum diameter, and maximum diameter may be determined and displayed. The various regions of the stent detected are shown in the prominent region of the middle profile view 21lb, with lumen L labeled as well as R1 and R2. In one embodiment, the area along the length of the stent in which the stent has been expanded to 90% or above the threshold is displayed as white, or as area 225. The Minimum Stent Area (MSA) in the vessel is also shown by cursor 227 and MSA in each figure. The expansion of the scaffold at MSA is shown to be about 48%. The references to white and red in the figures are only one example of distinguishing colors or indicia. Other indicia may be used in a given embodiment.

If stent under-expansion has been detected in one or more regions of the vessel that are part of the user interface, a marker 220 (e.g., red or another visual cue) may be used to display to the physician: the stent has been expanded to a region of a target expansion level (90% in this example), or a region above that expansion level, region 225.

The present disclosure relates in part to operations and methods performed on diagnostic data (e.g., intravascular data generated using a diagnostic system). Examples of such systems may include optical coherence tomography, intravascular ultrasound imaging, and other data intravascular data collection systems. The methods and systems described herein may perform one or more imaging pullbacks using various steps and processing stages to collect intravascular data. Each or a subset of the one or more pullback imaging sessions may also be imaged in parallel using the angiography system.

The present disclosure relates to various methods, systems, and devices related to stent detection and stent representation as part of a diagnostic and procedure information system adapted to assist in stent planning. The present disclosure includes, in part, embodiments AND features described in the patent application entitled "stent AND VESSEL VISUALIZATION AND DIAGNOSTIC SYSTEMS," STENT AND VESSEL vision AND DIAGNOSTIC SYSTEMS, DEVICES, AND METHODS, "filed on 24.7.7.3532 in U.S. patent application publication No. 20160022208, AND in the patent application entitled" METHOD AND APPARATUS FOR AUTOMATED DETERMINATION OF LUMEN profile OF STENTED VESSEL "(" metal AND APPARATUS FOR AUTOMATED detection OF LUMEN profile OF a LUMEN OF a STENTED VESSEL, "filed on 12.3.3.2013, AND U.S. patent application publication No. 20150297373, the entire disclosure OF each OF which is incorporated herein by reference.

The present disclosure is directed, in part, to computer-based methods, apparatuses, and systems for: the method, apparatus and system are adapted to image a blood vessel using one or more imaging modalities, co-register the imaging modalities, and represent the imaged blood vessel with a detected stent shown relative thereto. Under-expansion of the stent is also shown, as well as the level of expansion within a predetermined target level of expansion. Various systems and imaging modalities may be used to address the issue of how to properly expand a stent as disclosed herein. Additional details regarding the exemplary system are discussed herein (including with respect to fig. 1A and 1B). The following outputs of the system provide useful information: the output description is used to provide diagnostic guidance to address the technical challenges of stent expansion.

A two-dimensional view of the blood vessel with the labeled lumen L is shown in the graphical user interface panel 209. The line segment labeled B or Y corresponds to a segment in the bottom panel 215. An inner cavity contour panel 211 is shown in the middle of the entire interface 200. The lumen contour view has two central reference frames R1 and R2 that incorporate portions of the vessel in which the stent has been detected and is displayed in the illustrated representation.

Fig. 2B shows an enlarged view of the lumen profile 211 graphical user interface, wherein the end points of the stent are shown by the vertical dashed lines EP1 and EP 2. These end points of the stent are determined using the detected stent struts (which span a subset of the segment of the vessel).

In one embodiment, the offset distance is used to shift away from an edge of a first stent strut detected in the frame of image data and an edge of a last stent strut detected in the frame of image data. If the end stent struts throw geometric values that should be used to model the healthy lumen contour, the tapered contour interpolated using the first and second reference frames may be incorrectly modeled. Thus, a far-shifted offset or position along the vessel representation is selected which is moved a distance away from the end of the stent. These distances are shown in fig. 2B as D1 and D2. These may be used to generate the lumen profile 211a, the lumen profile 21la showing the tapered profile 290, the tapered profile 290 may be used as a basis for comparison with the stented lumen profiles described and depicted herein.

When placing a stent, it is advantageous to select a landing zone for normal/healthy tissue, which facilitates interpolation of a simulation of a healthy fully expanded vessel as a baseline comparator of lumen contours generated based on how the stent actually expands/under-expands. In one embodiment, a cursor or other on-screen user interface element is placed at both ends of the stented region, such as reference points R1 and R2. The cross-sectional area or another vessel parameter is automatically displayed with respect to each end of the stented region. The D1 and D2 offsets may be calculated by shifting away from the stent endpoint at R1, R2/EP1, EP 2.

Fig. 4A and 4B show a schematic representation of a blood vessel comprising one or more side branches as shown, which are adapted to generate a lumen contour model/representation of a healthy version of the imaged blood vessel for comparison with a recent stented and imaged blood vessel. Various methods may be used to interpolate the tapered profile to generate a basis for comparison with the actual level of stent expansion performed and measured after stent detection is complete.

The vessel being imaged (e.g., coronary artery) tapers from proximal to distal, and the size of the side branches in between affects the amount of tapering. As a tapered portion, the vessel diameter decreases when moving from the proximal side to the distal side. The stepwise decrease in diameter as one passes through the side branches is proportional to the diameter of the middle side branch. FIG. 4A shows the tapering due to the middle side branch SB, where D_proxIs the diameter of the proximal blood vessel, and D_distIs the diameter of the distal reference, B is the diameter of the medial side branch, and the range of scaling indices (exp) exceeds various values according to the models and related equations disclosed herein, and as disclosed herein.

The vessel taper profile or relationship for a single side branch may be used to calculate the ideal taper in the stented segment using the distal and proximal reference frames and the multiple medial side branches. As shown, in fig. 4B, a taper from the proximal section to the distal section is shown, along with two medial side branches. The increments can be calculated using vessel scaling laws

And

to provide a continuous taper reference from the proximal section to the distal section.

If there are a plurality of intermediate side branches as shown in FIG. 4B, the increment due to each side branch needs to be calculated, and the intermediate reference diameter D can be calculated_i. The intermediate reference diameter will then allow a continuous estimation of the taper from the proximal reference section to the distal reference section. Other interpolation techniques may also be used to generate the tapered contours. In one embodiment, the following relationship is used.

The side branch position and diameter can be measured while the distal and proximal reference frame diameters are known. Requires the calculation of an unknown single increment theta₁And theta₂. The following shows a generalized method for estimating the delta that can be used for any number of mid-side branches:

the difference between the proximal reference diameter and the distal reference diameter is:

d_proxis the diameter of the near-end reference frame, and d_distIs the diameter of the far-end reference frame.

θ_iAnd is the increment or step size from the far-end reference to the near-end reference at the ith branch, where there are a total of N branches. The segment increment at each branch is proportional to the diameter of branch B rising to the scaling law exponent.

Increment theta of ith branch to ith segment₁The contribution of (A) is:

the diameter of the reference profile in section i is calculated as:

in various embodiments, a tapered reference/tapered profile 290 is shown on the lumen profile, such as in fig. 3 and 7. An increment in the taper occurs at each automatically detected side branch, as shown on the lumen profile. The near-end frame and the far-end frame are automatically located using the stent detection feature. FIG. 3 also shows the location of the minimum expanded frame (EXP), and the percentage of expansion at that frame and the MSA frame.

The adaptive ideal reference contour is calculated using the natural taper of the vessel due to the side branch. There is a mathematical relationship between the distal and proximal references of equation 1 and the medial side branch.

Wherein D_proxIs the diameter of the proximal vessel, and D_distIs the diameter of the distal reference and B is the diameter of the medial side branch. In the case where no major side branch is detected between the distal and proximal references, the ideal lumen diameter for each location is calculated by using linear interpolation between the distal and proximal references.

In the case of multiple side branches, the ideal reference profile between the far and near reference frames tapers stepwise at each side branch, with larger side branches contributing proportionately larger steps. This can be seen in the dashed line of the tapered profile 290.

If the far-side reference frame and the near-side reference frame are in the same section, the stent contour is a linear interpolation between the far-side reference frame and the near-side reference frame. In one embodiment, a method for determining a target stent contour in response to one or more user-selected reference frames is as follows. The total number of side branches between the reference frames is input as N.

For example, if four (N-4) side branches between the most-distal frame and the most-proximal frame of the section are shown. The side branches are shown as SB in the figure, or as circles or dots as visual cues, e.g., the side branches in FIG. 1A are at the top of the lumen and three are disposed at the bottom. exp-2.3 is the scaling index. In one embodiment, the exp value ranges from greater than or equal to about 2 to less than or equal to about 3. The exp value describes the scalability of the taper of the section between the user-selected reference frames. In normal subjects, the exp value ranges from about 2.2 to about 2.7. In one embodiment, the exp value is about 7/3, or about 2.333. In other embodiments, exp is less than about 3.

d_proxis the diameter of the near-side reference frame, and d_distIs the diameter of the far-side reference frame.

θ_nIs the increment of the stent section at the nth branch (to be calculated)

The segment increment at each branch is proportional to the diameter of the branch that rises to the scaling law index.

Diameter of the stent in section n + 1:

the above segment diameters provide a delta measurement by which the boundaries of the upper and lower tapers of the target stent profile undergo a step change in magnitude (e.g., delta measurement) as the taper boundaries are generated across the vessel segment. This tapering, along with information about healthy regions in the vessel, can be used to interpolate the lumen profile representing a healthy vessel — it can be achieved by appropriate stent expansion over the entire length of the stent.

After the stent has been placed, the stent detection algorithm locates the stented luminal area. The lumen profile in the stented region is compared to a second lumen profile generated by interpolating between the first and second locations of the vessel by displacement distances D1 and D2 from the detected endpoints of the stent. The stent landing zones (which correspond to their respective end points) are associated with healthy tissue in the blood vessel. By displacing the distances D1 and D2 relative to the detected end points of the stent, the diameters, areas, chords, etc. of the two healthy lumens can be selected. These two selected distances are used, along with the tapered profile of the vessel and other vessel parameters and models, to interpolate the tapered profile 290, which tapered profile 290 may be shown in one or more lumen profile views.

Any over-or under-dilation can be determined by comparing the two lumen contour views (measured and interpolated) or the ratio, or other metric based on the geometric values at the same location of each contour. For each point along the stent, a ratio of values (e.g., diameters or areas from an interpolated lumen profile view (which indicates results from ideal stent expansion)) may be generated relative to corresponding area or diameter values of the lumen profile generated using the detected stent struts. The profile generated from the detected stent struts represents the level of expansion obtained when initially expanding a stent for positioning in a blood vessel using a balloon. The support is placed at the target landing zone. In one embodiment, the correlation with the zones selected to be healthy has been used as a measurable parameter to address the technical challenge of assessing stent expansion, based on the selection of these landing zones. These and other metrics may be used to generate tools for the end user as part of stent expansion assessment and correction.

The systems and software-based methods described herein may process frames of optical coherence tomography data obtained with respect to a vessel so that a stent disposed in the vessel may be evaluated or otherwise characterized. In one embodiment, each cross-sectional image may constitute a frame of OCT image data. For example, in one embodiment, such a stent is identified on a graphical user interface showing a three-dimensional image or a two-dimensional image of a blood vessel generated using collected image data.

The software modules and stented vasodilation stenting assessment and display features described herein may be implemented using non-transitory computer readable storage media. In one embodiment, a non-transitory computer readable storage medium stores a program that, when executed by a computing device, causes the computing device to perform a method for processing or otherwise manipulating intravascular image data and intravascular parameters. Each method may include one or more steps as outlined herein.

The systems and software-based methods described herein may process frames of optical coherence tomography data obtained with respect to a vessel so that a stent disposed in the vessel may be evaluated or otherwise characterized. In one embodiment, each cross-sectional image may constitute a frame of image data. For example, in one embodiment, such a stent is identified on a graphical user interface as follows: the graphical user interface shows a three-dimensional image or a two-dimensional image of the blood vessel generated using the collected image data.

The software modules and stented vasodilation assessment and display features described herein may be implemented using non-transitory computer-readable storage media. In one embodiment, a non-transitory computer readable storage medium stores a program that, when executed by a computing device, causes the computing device to perform a method for processing or otherwise manipulating intravascular image data and intravascular parameters. Each method may include one or more steps as outlined herein. In one embodiment, the stent expansion threshold is in a range of about 90% to about 100%. In one embodiment, the stent expansion threshold is in a range of about 80% to about 90%. In one embodiment, the stent expansion threshold is in a range of about 85% to about 95%. In one embodiment, the stent expansion threshold is in a range of about 75% to about 85%.

Non-limiting software features and embodiments for implementing stent expansion assessment and user feedback

The present disclosure relates in part to computer-based methods, systems, and apparatus for visualizing stents. In one embodiment, the present disclosure relates to a method of: the stented vessel is evaluated for expansion and whether further expansion is required, or whether repositioning of the stent is required. Methods of these evaluations may include displaying one or more views of the stent in various states (e.g., expanded state relative to the vessel) and comparing the imaged stent against one or more selected stent contours. In one embodiment, the method is performed automatically. The methods of the present disclosure may be implemented using software (e.g., stent contour analysis software) that may include stent planning software and lesion preparation software (or vice versa).

The stent to be placed can be selected using OCT, IVUS, angiography, or other probe data obtained with respect to the stentless vessel segment and subsequently compared to the stented vessel. The stented and non-stented phases of the stent plan may then be displayed as expanded or unexpanded states, either longitudinally or in cross-sectional view, as part of one or more Graphical User Interfaces (GUIs). Such an interface may include one or more views of the blood vessel generated using a distance measurement obtained using an OCT system, IVUS system, angiography system, or other data collection system.

A second pullback may be performed just after placement of the stent so that further expansion or repositioning or removal can be performed. These may result in saving valuable time and the need for a follow-up procedure.

An exemplary image processing pipeline 350 is depicted in figure 8 for transforming the collected OCT data into two-dimensional and three-dimensional views of the vessel and stent, and comparing the contours against stent deployment. The image data processing pipeline or any of the methods described herein is stored in memory and executed using one or more computing devices (e.g., processors, devices, or other integrated circuits). In one embodiment, computing device 340 includes or has access to software modules or programs, such as a side branch detection module, a guidewire detection module, a lumen detection module, stent deployment analysis software, stent expansion analysis and display software (e.g., software 67 of fig. 1A), and other software modules. The software modules or programs may include an image data processing pipeline or component modules thereof, and one or more Graphical User Interfaces (GUIs).

As shown in fig. 8, one or more displays 346 may be used to display the following information: for example, cross-sectional and longitudinal views of a blood vessel, such as the blood vessel segment views and contours shown and disclosed herein, are generated using collected intravascular data and angiographic data. These displays 346 may be arranged as shown in FIG. 1B. The information may be displayed using one or more Graphical User Interfaces (GUIs). Further, the information may include, but is not limited to: cross-sectional scan data, longitudinal scans, lumen profiles, VRR values, FFR values, stents, malpositioned areas, lumen boundaries, contra-lateral branches, and other images or representations of blood vessels or potential distance measurements obtained using the system 355 and data collection probe. In one embodiment, the computing device 340 may also include software or programs 344, which may be stored in one or more memory devices, configured to identify target stent contours, lumen contours, and stent expansion values, as well as target and other vessel features, such as with text, arrows, color coding, highlighting, contour lines, or other indicia suitable for human or machine readable. The software module pipeline may include features for supporting and providing stent expansion analysis and display. Various markers may be applied via the marker application module 370 to emphasize and distinguish any and all of the detected and generated arterial image data and the generated contour view and stent-related parameters.

Once the image data is obtained with a probe or other imaging system (e.g., an angiography system) for OCT or IVUS image data, it is stored in memory; it may be processed to generate information (e.g., a cross-sectional, longitudinal, and/or three-dimensional view of the vessel along the length of the pullback region, or a subset thereof). These views may be depicted as part of the user interface depicted in the various figures. An image of a blood vessel generated using distance measurements obtained from an OCT system provides information about the blood vessel and an object disposed therein.

As shown, the pipeline may receive the post-stent deployment pullback data 352 (the post-stent deployment pullback data 352 would appear after the initial pullback) to image the vessel. The user selection may be received via the GUI and the stent planning data may be transferred to stent contour or stent deployment analysis software (e.g., software 67 in fig. 1A). Guidewire 354, side branch detection 356, stent detection 358, and lumen detection module 360 may operate on rear stent deployment pullback data (which may be collected by the scan lines). The stent expansion analysis and display software 362 may perform various steps as described herein, for example, evaluating the detected stent relative to the detected lumen profile, calculating stent expansion, calculating MSA, measuring stent parameters, and showing the expansion levels of the stent at different frames along the artery, as well as other features and methods as disclosed herein. In addition, the pipeline may include co-registration software for co-registering the angiographic data and the intravascular data to show stent expansion data relative to the angiographic data. In one embodiment, stent expansion is assessed using data from two or more intravascular imaging pullback sessions, wherein the probe is pulled back through a portion of the artery.

The following description is intended to provide an overview of device hardware and other operating components suitable for performing the methods of the disclosure described herein. The description is not intended to limit the applicable environments or scope of the present disclosure. Similarly, hardware and other operational components may be suitable as part of the devices described above. The present disclosure may be practiced with other system configurations, including personal computers, multiprocessor systems, microprocessor-based or programmable electronics, network PCs, minicomputers, mainframe computers, and the like. The present disclosure may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network (e.g., in a catheter laboratory or a different room of a tube laboratory).

Some portions of the detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations may be used by those skilled in the computer and software related arts. An algorithm is here, and generally, considered to be a self-consistent sequence of operations leading to a desired result, in one embodiment. The operations that are stopped as a method or performed in other ways than those described herein are those requiring physical manipulations of physical quantities. Typically (but not necessarily), these amounts take the form: electrical or magnetic signals capable of being stored, transferred, combined, transformed, compared, and otherwise manipulated.

Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing" or "computing," "covering" or "searching" or "detecting" or "measuring" or "computing" or "comparing" or "generating" or "determining" or "displaying" or the like, refer to the actions and processes of a computer system or electronic device, the computer system or electronic device manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers or electronic device registers and memories into other data similarly represented as physical quantities within electronic memories or registers or other such information storage, transmission or display devices.

In some embodiments, the present disclosure also relates to apparatuses for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general purpose computer selectively activated or reconfigured by a computer program stored in the computer.

Embodiments of the disclosure may be embodied in many different forms, including, but not limited to, computer program logic for use with a processor (e.g., a microprocessor, microcontroller, digital signal processor, or general purpose computer), programmable logic for use with a programmable logic device (e.g., a Field Programmable Gate Array (FPGA), or other programmable logic device), discrete components, integrated circuits (e.g., an Application Specific Integrated Circuit (ASIC)), or any other device including any combination thereof. In typical embodiments of the present disclosure, some or all of the processing of data collected using the OCT probe and the processor-based system is implemented as a set of computer program instructions that are converted into a computer-executable form, stored in, for example, a computer-readable medium, and executed by a microprocessor under the control of an operating system. Thus, the query response and the input data are transformed into processor understandable instructions suitable for generating imaging data, detecting lumen boundaries, detecting stent struts, comparing measured vertical distances against set thresholds, and otherwise performing image comparisons, signal processing, lumen detection, stent detection, and comparing detected stents and other features and embodiments described above.

Computer program logic implementing all or part of the functionality previously described herein may be embodied in various forms, including, but not limited to, source code forms, computer executable forms, and various intermediate forms (e.g., forms generated by an assembler, compiler, linker, or locator). The source code may include a series of computer program instructions implemented in any of a variety of programming languages, such as object code, assembly language, or a high-level language (e.g., Fortran, C + +, JAVA, or HTML) for use with various operating systems or operating environments. The source code may define and use various data structures and communication messages. The source code may be in computer-executable form (e.g., via an interpreter), or the source code may be converted (e.g., via a translator, assembler, or compiler) into computer-executable form.

A computer program may be fixed, permanently or temporarily, in any form (e.g., source code form, computer-executable form, or intermediate form) in a tangible storage medium, such as a semiconductor memory device (e.g., RAM, ROM, PROM, EEPROM, or flash programmable RAM), a magnetic memory device (e.g., a disk or fixed disk), an optical memory device (e.g., a CD-ROM), a PC card (e.g., a PCMCIA card), or other memory device. The computer program may be fixed in any form in a signal that can be transmitted to a computer using any of a variety of communication techniques, including but not limited to, analog techniques, digital techniques, optical techniques, wireless techniques (e.g., bluetooth), networking techniques, and internet techniques. The computer program may be distributed in any form as a removable storage medium with the following accompanying items: printed or electronic documents (e.g., compressed software packages), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic billboard via a communications system (e.g., the internet or world wide web).

Hardware logic (including programmable logic used with programmable logic devices) that implements all or part of the functionality previously described herein may be designed using conventional manual methods, or may be designed, obtained, simulated, or electronically documented using various tools, such as Computer Aided Design (CAD), hardware description languages (e.g., VHDL or AHDL), or PLD programming languages (e.g., PALASM, ABEL, or CUPL).

Programmable logic may be permanently or temporarily fixed in a tangible storage medium such as a semiconductor memory device (e.g., RAM, ROM, PROM, EEPROM, or flash programmable RAM), a magnetic memory device (e.g., a disk or fixed disk), an optical memory device (e.g., a CD-ROM), or other memory device. The programmable logic may be fixed in a signal that may be transmitted to a computer using any of a variety of communication techniques, including but not limited to analog techniques, digital techniques, optical techniques, wireless techniques (e.g., bluetooth), networking techniques, and networking techniques. Programmable logic may be distributed as a removable storage medium with the following accompanying things: printed or electronic documents (e.g., compressed software packages), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the communication system (e.g., the internet or world wide web).

Various examples of suitable processing modules are discussed in more detail below. As used herein, a module refers to software, hardware, or firmware adapted to perform a particular data processing or data transmission task. In general, in a preferred embodiment, a module refers to a software routine, program or other memory-resident application adapted to receive, transform, route and process instructions, or various types of data (e.g., OCT scan data, IVUS scan data, interferometer signal data, target stent contours, post-stent deployment lumen contours and images, interpolated lumen contour views indicative of a fully expanded stent, geometric values based on the ratio of the expanded stent lumen contour to the fully expanded lumen contour, stent expansion level markers (colors, shading, etc.), highlight/emphasize pixel attributes, side branch positions, side branch diameters, stent expansion percentages or fractions, pre-stent FFR values, post-stent FFR values, and other pre-and post-stent values, as well as other information of interest).

The computers and computer systems described herein may include an operatively associated computer-readable medium, e.g., memory, for storing a software application for obtaining, processing, storing, and/or communicating data. It will be appreciated that such memory may be internal, external, remote, or local with respect to the computer or computer system with which it is operatively associated.

The memory may also include any means for storing software or other instructions, including (for example, but not limited to): hard disk, optical disk, floppy disk, DVD (digital versatile disk), CD (compact disk), memory stick, flash memory, ROM (read only memory), RAM (random access memory), DRAM (dynamic random access memory), PROM (programmable ROM), EEPROM (erasable programmable PROM), and/or other similar computer-readable medium.

In general, computer-readable memory media employed in association with embodiments of the disclosure described herein may include any memory medium capable of storing instructions for execution by a programmable device. Where applicable, the method steps described herein may be embodied or performed as instructions stored on a computer-readable memory medium or storage medium. These instructions may be software implemented in various programming languages (e.g., C + +, C, Java, and/or various other software programming languages that may be applied to create instructions in accordance with embodiments of the present disclosure).

The storage medium may be non-transitory or comprise a non-transitory device. Thus, a non-transitory storage medium or non-transitory device may comprise a tangible device, meaning that the device has a particular physical form, although the device may change its physical state. Thus, for example, non-transient refers to: despite this change in state, the device remains tangible.

The aspects, embodiments, features and examples of the present disclosure are to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being limited only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed disclosure.

The use of headings and chapters in this application is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the present disclosure.

Throughout this application, where a composition is described as having, containing, or comprising a particular component, or where a method is described as having, containing, or comprising a particular process step, it is contemplated that the composition of the present teachings also consists essentially of, or consists of, the recited component, and the method of the present teachings also consists essentially of, or consists of, the recited process step.

In the present application, where an element or component is referred to as being included in and/or selected from a list of said elements or components, it is to be understood that the element or component can be any one of the recited elements or components and can be selected from the group consisting of two or more of the recited elements or components. Moreover, it should be understood that elements and/or features of a composition, an apparatus, or a method described herein may be combined in various ways without departing from the spirit and scope of the present teachings, whether explicit or implicit.

The use of the terms "comprising," "including," "containing," "having," or "possessing" is generally to be understood as open-ended and non-limiting unless specifically stated otherwise.

The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. In addition, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Further, to the extent that the term "about" or "substantially" is used before a quantitative value, the present teachings also encompass the specific quantitative value itself, unless specifically stated otherwise. The terms "about" and "substantially" as used herein refer to a change that can occur in a quantity, for example, by measuring or processing a process in the real world; through inadvertent errors in these processes; through discrepancies/failures in material (e.g., composite tape) fabrication, through defects; and equivalents thereof as recognized by those skilled in the art, provided such variations do not contain known values from prior art practices. Generally, the terms "about" and "substantially" refer to a value or range of values greater than or less than the value represented by 1/10 of the stated value, e.g., ± 10%.

It should be understood that the order of steps or order for performing certain actions is immaterial so long as the present teachings remain operable. Further, two or more steps or actions may be performed simultaneously.

The use of headings and chapters in this application is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the present disclosure. It is intended that only those claims using the word "means for … …" be interpreted in accordance with 35USC 112 section six. In the absence of a "means for … …" in a claim, such claim should not be construed in light of 35USC 112. No limitations in the specification are intended to be construed as limitations in any claim unless such limitations are explicitly included in the claims.

When values or ranges of values are given, each value and the endpoints of the given ranges and values therebetween can be increased or decreased by 20% while still remaining within the teachings of the present disclosure unless some different range is specifically mentioned.

Where a range or list of values is provided, each intervening value, between the upper and lower limit of that range or list of values, is considered individually and is encompassed within the disclosure as if each value was specifically recited herein. Moreover, smaller ranges between and including the upper and lower limits of a given range are contemplated and are included within the present disclosure. The list of exemplary values or ranges does not forego other values or ranges between (and including) the upper and lower limits of the given range.

It is to be understood that the figures and descriptions of the present disclosure have been simplified to illustrate elements that are relevant for a clear understanding of the present disclosure, while eliminating, for purposes of clarity, other elements. However, one of ordinary skill in the art will recognize that these and other elements may be desirable. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present disclosure, a discussion of such elements is not provided herein. It should be understood that the drawings are presented for illustrative purposes and not as a construction drawing. Omitted details and modifications or alternative embodiments are within the purview of one of ordinary skill in the art.

It is to be understood that in certain aspects of the present disclosure, a single component may be replaced by multiple components, and multiple components may be replaced by a single component to provide an element or structure, or to perform a given function or functions. Unless such substitutions would not be operable to practice certain embodiments of the present disclosure, such substitutions are considered to be within the scope of the present disclosure.

The examples presented herein are intended to illustrate potential and specific implementations of the invention. It is understood that these examples are primarily for the purpose of illustrating the disclosure to those skilled in the art. There may be variations to these diagrams or the operations described herein without departing from the spirit of the disclosure. For example, in some cases, method steps or operations may be performed or performed in a different order, or operations may be added, deleted or modified.

Claims

1. A method of evaluating stent expansion in a vessel defining a lumen, comprising:

scanning the stented vessel using a first imaging system to obtain a first set of vessel image data;

storing the first set of blood vessel image data in an electronic memory device in electronic communication with the first imaging system;

detecting stent struts along a length of the stented vessel using one or more software modules;

generating a first representation of a section of the blood vessel indicative of a level of stent expansion;

determining a first end of the stent and a second end of the stent using the detected stent struts;

defining a first offset distance (D1) from the first end of the bracket and a second offset distance (D2) from the second end of the bracket;

generating a second representation of the section of the blood vessel using D1 and D2 in conjunction with a tapered profile of the section; and

determining a level of stent expansion of interest along a vessel segment by comparing a first value associated with the first representation and a second value associated with the second representation at different locations along the length of the segment.

2. The method of claim 1, wherein the vessel receives one or more stents during a first procedure, wherein the scanning of the stented vessel is performed as an extension of the first procedure as a diagnostic analysis.

3. The method of claim 1, wherein the first representation is a first lumen profile of the stented vessel, wherein the lumen profile is generated based on an actual level of expansion of the stent along a length of the segment.

4. The method of claim 3, wherein the second representation is a second lumen profile generated based on geometric values of the vessel at each of D1 and D2, wherein the second lumen profile is interpolated based on the geometric values of the vessel and the tapered profile.

5. The method of claim 4, further comprising detecting one or more side branches along the section, wherein the interpolation of the second cavity profile is generated using the one or more detected side branches.

6. The method of claim 4, wherein the geometric value of a vessel is selected from the group consisting of an area, a diameter, a chord, a Euclidean distance metric, and a volume.

7. The method of claim 4, wherein determining a level of target stent expansion further comprises determining a degree of stent expansion relative to a stent expansion threshold using a ratio of the first value of a first lumen profile and the second value of the second lumen profile at a plurality of locations along the segment.

8. The method of claim 1, wherein the first representation comprises one or more views of the blood vessel, wherein the one or more views of the blood vessel display representations of the detected stent struts and the lumen of the blood vessel.

9. The method of claim 1, wherein the scanning of the stented vessel is performed using optical coherence tomography, angiography, ultrasound, x-ray, optical imaging, pressure sensing, flow sensing, and tomographic imaging.

10. The method of claim 1, wherein the scanning of the stented vessel is performed using an intravascular data collection probe that is pulled back through the vessel.

11. The method of claim 1, wherein the scanning of the stented vessel is performed using one or more shadows or reflections from the first set of vessel image data.

12. The method of claim 1, wherein D1 and D2 are selected based on proximity to a user selected target landing zone when placing the stent.

13. The method of claim 1, further comprising: after deploying the stent in the vessel, a vessel lumen contour is generated using one or more computing devices.

14. The method of claim 1, further comprising: displaying one or more views of the vessel and/or the first vessel representation, and displaying one or more visual cues indicating regions of stent under-expansion along the length of the vessel segment.

15. The method of claim 1, further comprising detecting a side branch along a length of the section of the blood vessel and displaying the side branch relative to the lumen.

16. The method of claim 15, wherein the side branch is displayed as a point, an ellipse, a circle, or other shape relative to the first representation.

17. The method of claim 1, wherein the first representation is displayed using a user interface of an imaging system.

18. The method of claim 1, further comprising scanning a vessel using an angiography system, and co-registering angiography data with detected stent struts and first and second visual cues, wherein the first visual cue indicates stent expansion above a stent expansion threshold and the second visual cue indicates stent expansion below the stent expansion threshold.

19. The method of claim 1, further comprising visually emphasizing an area comprising the first representation of the stent.

20. The method of claim 19, wherein the user interface emphasizes the region by changing a contrast, intensity, color of another visual element relative to the region.

21. The method of claim 4, wherein D1 and D2 are selected from a distance in the range of about 0.1mm to about 1.0 mm.

22. The method of claim 1, further comprising detecting one or more side branches along a segment, wherein determining the tapered profile of the segment comprises adjusting the profile based on a diameter of at least one detected side branch.

23. The method of claim 1, further comprising determining a minimum dilated frame and displaying an indication of the minimum dilated frame.

24. A processor-based system for assessing stent expansion in a stented vessel, comprising:

one or more memory devices; and

a computing device in communication with the memory device, wherein the memory device includes instructions executable by the computing device to cause the computing device to:

storing a first set of vessel image data in an electronic memory device in electronic communication with a first imaging system, the first set of vessel image data generated by scanning the vessel using the first imaging system;

detecting stent struts along a section of the stented vessel using one or more software modules;

generating a second representation of the segment of the blood vessel using D1 and D2 in combination with the tapered profile of the segment; and

determining a level of target stent expansion along a vessel segment by comparing a first value associated with the first representation and a second value associated with the second representation at different locations along the segment.

25. The system of claim 24, wherein the first value is a first area or a first diameter, wherein the second value is a second area or a second diameter.